The invention relates to improvements in sifters or separators having a plurality of concentric rotatably mounted rotors wherein particulate material and air passes through the rotors and fractions of material are separated.
The separator is commercially useful separating various types of commercial materials but in particular is well suited for separating such materials as the output from a cement processing kiln and such as the output from a high pressure press operating as an interparticle crushing press and delivering particulate material and agglomerates.
German Patent Application P 39 24 826.7 discloses a separator of the above type wherein separating rotors are arranged at a distance above one another. A separate conduit for the sifting air admission and a separate conduit for the sifting air discharge are provided for each sifter rotor. This arrangement is intended to prevent fine material from proceeding into the middlings and middlings from proceeding into the coarse material when sifting granular particulate material so that a clear separation of the respectively desired grain fractions from one another is obtained with a high yield well suited for commercial production.
In such separators, it is necessary to obtain a high continuous output of sufficient capability to handle the output of a press or other machinery preceding the separator. Also, the mechanism must be capable of improved clear separation without intermixing of the fractions.